Paul danckwardt



(No Model.)

P. DANCK-WARDT. .APPARATUS PoR AND PROCESS oP RXTRAGTING GOLD 0R SILVERPROM oRRS.

Patented Sept. 18, 1894.

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UNITED STATES PATENT OFFICE.

PAUL DANCKVARDT, OF NEW' YORK, N. Y., ASSIGNOR OF ONE-HALF TO CHARLESDOEHRING, OF SAME PLACE.

APPARATUS FOR AND PROCESS 0F EXTRACTING GOLD OR SILVER FROM ORES.

SPECIFICATION forming part of Letters Patent No. 526,099, datedSeptember 18, 1894.

' Application filed April 2, 1894. Serial No. 505,999. (No model.)

To OZZZ whom/.it may concern:

Be it known that I, PAUL DANCKWARDT, of New York city, New York, haveinvented an Improved Apparatus for and Process of Extracting Gold orSilver from Ores, of which thefollowing is a specification.

This invention relates to an improved apparatus and process forextracting gold and silver from ores by electrolysis.

yIt consists essentially in treating the ores in a finely pulverizedstate with a solution of cyanide of potassium and ammonium sullide, oranother alkali sulfide, and subjecting it simultaneously to the actionof an electric current and an amalgamated cathode.

In the accompanying drawings, Figure l is a cross section of myimprovedapparatus, on

line 1, 1, Fig 2. Fig. 2 is a longitudinal sec! tion, partly inelevation, of the same, and Fig. 3 a cross section, partly in elevation,of a supplemental apparatus.

The letter a, represents an iron cylinder provided with a lead lining b,and revolved by a belt c', and toothed wheel c, that engages a toothedwheel c2, embracing the cylin/der. The heads a', of the cylinder a, aremade of annular shape and receive Within their central opening, a seconddrum or cylinder cZ, composed of amalgamated sheet copper. vThiscylinder closes the openings within the heads a', and is insulated fromsuch heads. The insulation is effected preferably by a rubber packing e,that embraces the inner edge of heads a', and to which a metal ring e',is connected by bolts e2. To this ring in turn the cylinder d, issecured by screws e3.

To the inner periphery of cylinder a, there are secured a number ofinclined radial blades f, that reach to within a short distance ofcylinder CZ, and serve to shovel the ore in thin streams slowly over thesurface of the inner cylinder. The electricity is conveyed to theapparatus by the contact springs g, h, connected respectively to thecylinders d, a, and of which the cylinder a, constitutes the anode, andthe cylinder oZ, the cathode.

In use the pulverized ore is introduced into the apparatus through doort', together with a solution of cyanide of potassium and ammoniumsulfide, or another alkali sulfide. The proportions should be for oneton of ore,

about ten pounds cyanide of potassium and two to three pounds ofammonium sulfide. The door is then closed, the drum is rotated and aconstant current of electricity under low tension is turned on. Thiscurrent will cause the gold and silver to be separated at the anode andto be deposited upon the amalgamated cathode. The alkali sulfide willreduce the consumption of cyanide of potassium to a minimum, because itwill prevent the formation of soluble combinations between any of theraw metal combinations and part of the cyanide of potassium. Moreoverthe alkali sulfide will favor the solution of certain silvercombinations, because the electric current will cause a partialoxidation of the sulfide, into hyposulite, which will thus be able toexert its dissolving power upon the silver combinations.

After the apparatus has rotated for several hours, all or nearly all ofthe gold and silver is deposited upon the inner cylinder OZ, in the formof amalgam. If this precipitation has been perfect, the apparatus isarrested, the inner cylinder is removed and the amalgam is scraped off.This amalgam is heated in a retort to obtain a gold and silver alloy,and the filtered solution goes to a storage tank to be used over again.If however the precipitation upon the inner cylinder should not havebeen perfect, I prefer to employ the auxiliary apparatus illustrated inFig. 3. This apparatus is a modification of the one illustrated in Figs.1 and 2, and consists of a series of semi-cylindrical tanks Zt, arrangedone below the other.A Each tank contains a revolublc cylinder Z, hung onshaft Z, which is insulated from tank lc, by rubber washer Z2. Thedistance between cylinder and tank should be about four centimeters, thedrawings showing such distance enlarged for the sake of clearness.

The tanks 7c, are amalgamated upon their inner side and contain a littlemercury besides the solution to be treated. Each tank la, is connectedwith the negative pole of an electric generator by coil n, while thecylinder Z, is connected to the positive pole by coil n', andconstitutes the anode. The filtered solution taken from the mainapparatus is introduced into the uppermost tank k, by

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pipe p. All the cylinders l, are rotated and a constant current ofelectricity under low tension is turned on. As soon as the uppermosttank has become filled, the solution will enter the second tank by pipeAp', and thence through pipe p2, the third tank, to finally leave theapparatus through pipe p3, free from gold and silver. The latter isdeposited in the form of amalgam upon the bottom of the tanks.

I employ the auxiliary apparatus generally for precipitating any cyanidesolutions that contain gold and silver, and especially for precipitatingsolutions of gold and silver and cyanide of potassium.

That I claim is- 1. The process of extracting gold and silver from oreswhich consists in subjecting the same simultaneously to the action ot'cyanide of potassium, an alkali sulfide and. to electrolysis,substantially as specied.

2. The combination of au outer revolving drum with an inner insulatedamalgamated drum, blades secured to the outer drum, and electricconnections secured to the outer and inner drum, substantially asspecified.

3. The combination of a series of communicating tanks with revolvinginsulated drums hung Within such tanks, and with electric connectionssecured to the tanks and drums, substantially as specified.

4. The combination of a main apparatus consisting of a revolving outerdrum having blades, an insulated inner drum and electric connections,with an auxiliary apparatus consisting of a series of communicatingtanks, rotating insulated drums and electric connections, substantiallyas specitied.

In testimony whereof I have signed this specification this 28th day ofMarch, 1894.

PAUL DANOKWARD'I. Witnesses:

F. v. BRIESEN, WILLIAM SCHULZ.

